Epsilon Andromedae

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ε Andromedae
Andromeda stars.png
Location of ε Andromedae (lower left of center)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Andromeda
Right ascension 00h 38m 33.3458s[1]
Declination +29° 18′ 42.305″[1]
Apparent magnitude (V) 4.37[1]
Spectral type G6 III Fe−3 CH1[2]
U−B color index +0.47[2]
B−V color index +0.87[2]
V−R color index 0.6[1]
R−I color index +0.51[2]
Radial velocity (Rv) −83.6 ± 0.9[1] km/s
Proper motion (μ) RA: −229.42[1] mas/yr
Dec.: −254.09[1] mas/yr
Parallax (π) 19.34 ± 0.76[1] mas
Distance 169 ± 7 ly
(52 ± 2 pc)
Absolute magnitude (MV) +0.69[3]
Mass 2.00 M
Radius 9.8[4] R
Luminosity 56 L
Surface gravity (log g) 2.09 cgs
Temperature 4,882 K
Metallicity [Fe/H] −0.67 dex
Rotational velocity (v sin i) 9[2] km/s
Age 891 Myr
Other designations
ε And, Epsilon Andromedae, Epsilon And, 30 Andromedae, 30 And, BD+28 103, FK5 19, GC 759, HD 3546, HIP 3031, HR 163, LTT 10215, NLTT 2065, PPM 90002, SAO 74164.[1]
Database references

Coordinates: Sky map 00h 38m 33.3458s, +29° 18′ 42.305″

Epsilon Andromedae (Epsilon And, ε Andromedae, ε And) is a G-type giant star in the constellation of Andromeda.[1] It has an apparent visual magnitude of approximately 4.37.[1]

ε Andromedae is believed to be a red clump star which is fusing helium in its core. Its orbit in the Milky Way is highly eccentric, causing it to move rapidly relative to the Sun and its neighboring stars.[5]


In Chinese, 奎宿 (Kuí Sù), meaning Legs (asterism), refers to an asterism consisting of ε Andromedae, η Andromedae, 65 Piscium, ζ Andromedae, δ Andromedae, π Andromedae, ν Andromedae, μ Andromedae, β Andromedae, σ Piscium, τ Piscium, 91 Piscium, υ Piscium, φ Piscium, χ Piscium and ψ¹ Piscium. Consequently, ε Andromedae itself is known as 奎宿四 (Kuí Sù sì, English: the Fourth Star of Legs.)[6]


  1. ^ a b c d e f g h i j k NLTT 2065 -- High proper-motion Star, database entry, SIMBAD. Accessed on line August 28, 2008.
  2. ^ a b c d e HR 163, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line August 28, 2008.
  3. ^ a b Takeda, Yoichi; et al. (August 2008), "Stellar Parameters and Elemental Abundances of Late-G Giants", Publications of the Astronomical Society of Japan, 60 (4): 781–802, Bibcode:2008PASJ...60..781T, arXiv:0805.2434Freely accessible, doi:10.1093/pasj/60.4.781. 
  4. ^ Nordgren, Tyler E.; et al. (December 1999), "Stellar Angular Diameters of Late-Type Giants and Supergiants Measured with the Navy Prototype Optical Interferometer", The Astronomical Journal, 118 (6): 3032–3038, Bibcode:1999AJ....118.3032N, doi:10.1086/301114 
  5. ^ Epsilon Andromedae, Stars, Jim Kaler. Accessed on line August 28, 2008.
  6. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日

External links[edit]